Document breaking changes in 4.3.0 & 4.4.0

[brodycj]

Platforms affected

iOS

Motivation and Context

see issue #1040 & apache/cordova-plugin-inappbrowser#831

closes #1040

Description

see title

Testing

N/A

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary

[codecov-io]

Codecov Report

Merging #1041 (b723e10) into master (be1cd7d) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1041   +/-   ##
=======================================
  Coverage   74.82%   74.82%           
=======================================
  Files          13       13           
  Lines        1720     1720           
=======================================
  Hits         1287     1287           
  Misses        433      433           

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